A rear seat region in a vehicle room is lower in cooling/heating efficiency than a front seat region where an air conditioning system is installed. Thus, it is important to enhance the cooling/heating efficiency in the rear seat region.
As a method of enhancing the cooling/heating efficiency in the rear seat region, there is available a technique of independently cooling and heating a rear seat region in a vehicle room.
In this technique, as shown in FIG. 1, a rear control switch. 12 of a front seat controller 10 is turned on by a user. Then, a rear seat set temperature and a rear seat air volume level are inputted by individually operating a rear seat temperature adjustment switch 14 and a rear seat air volume adjustment switch 16 of a front seat controller 10 or a rear seat temperature adjustment switch 22 and a rear seat air volume adjustment switch 24 of a rear seat controller 20. As a result, the temperature and air volume of the air blown toward a rear seat region 30 are independently controlled according to the rear seat set temperature and the rear seat air volume level thus inputted.
Thus, the rear seat region 30 in the vehicle room is independently cooled and heated. This makes it possible to enhance the cooling/heating efficiency of the rear seat region 30 and to improve the pleasantness in the rear seat region 30.
In the course of independently cooling and heating the rear seat region 30, when the air discharge mode of an air conditioning system is manually or automatically controlled to a defrosting mode, the cooling or heating of the rear seat region 30 is stopped. Specifically, an auxiliary blower (not shown) for a rear seat is turned off so that the air is not blown toward the rear seat region 30.
The reason for employing this configuration is to supply the air, which was previously supplied to the rear seat region 30, to the glass windows of the front seat region (not shown). This makes it possible to increase the volume of the air discharged toward the glass windows of the front seat region, thereby enhancing the defrosting efficiency on the glass windows.
During the control in the defrosting mode, even if the rear seat controller 20 is operated, the cooling or heating of the rear seat region 30 is continuously kept stopped. This is because the defrosting in the glass windows has a higher priority than the cooling or heating of the rear seat region 30. Thus, in the defrosting mode, it is possible to avoid a reduction in the volume of the air discharged toward the glass windows and to enhance the defrosting efficiency on the glass windows.
In the conventional air conditioning system mentioned above, if the air conditioning system is controlled in the defrosting mode while cooling or heating the rear seat region 30, the cooling or heating of the rear seat region 30 is suddenly stopped. In this case, a vehicle occupant in the rear seat region 30 may misunderstand that the cooling or heating of the rear seat region 30 is in error or failure.
In particular, the cooling or heating of the rear seat region 30 is continuously kept stopped even though a vehicle occupant in the rear seat region 30 operates the rear seat controller 20. Therefore, the vehicle occupant in the rear seat region 30 may misunderstand that the air conditioning system suffers from severe trouble.
In view of this, there has been proposed a technique of, when an air conditioning system is controlled in a defrosting mode, turning off a display unit 26 of the rear seat controller 20 and indicators 22a and 24a of individual switches 22 and 24, notifying a vehicle occupant of the fact that the cooling or heating of the rear seat region 30 is stopped.
In this conventional technique, when the air conditioning system is controlled in the defrosting mode, the display unit 26 of the rear seat controller 20 and the indicators 22a and 24a of the individual switches 22 and 24 are turned off. This may deepen the misunderstanding that the cooling or heating of the rear seat region 30 is out of order.